Removing Muscle Tension: Wrench & Bolt Analogy
Our muscles have the ability to perform three different types of contractions: Concentric, Isometric, and Eccentric (pronounced ee-centric). DCT techniques utilize these three contractions to remove muscle tension from the body.
A concentric contraction is when a muscle moves from a lengthened to shortened position while under resistance. This type of contraction is the most commonly used during weight lifting [exercise].
An isometric contraction is when a muscle is held at a fixed length while under resistance (i.e., the muscle contracts without lengthening or shortening.) This type of contraction is frequently used in Pilates and other stabilization-based activities.
An eccentric contraction is when a muscle moves from a shortened to lengthened position while under resistance. This type of contraction is used when walking down stairs or on a decline as well as in several forms of weight training (e.g. negatives).
The following Wrench and Bolt Analogy helps to illustrate the mechanics of tension accumulation and release within muscle tissue.
Wrench and Bolt Analogy:
When a person uses concentric contractions to do bicep curls, it is similar to using a wrench to screw a bolt into a piece of wood. After each repetition, a certain amount of tension is pulled into the muscle tissue just like a bolt (i.e. knot) being screwed (i.e. concentric contraction) deeper into the piece of wood (i.e. muscle tissue).
And because tension is essentially “screwed” into muscle tissue, the only way to effectively and permanently release accumulated tension is by unscrewing it. The best massage therapist in the world could spend an endless amount of time trying to massage the bolt out of the wood but would have no success. The massage will affect the tissue surrounding the knot making the area feel softer to the touch and giving the impression that the tension has been removed while in truth the knots are still there. This is why several days after a massage the effects on the soft tissue surrounding the knots subside and the “tension” reappears. Because knots are “screwed” into the body, massage and other modalities that don’t have the tools to unscrew them (i.e. eccentric contractions) are simply not effective [over time] at removing them. (However these other modalities do have benefits which we will discuss soon)
The only way to remove the bolt from the wood is by unscrewing it. And muscle tension in the body is removed in the same way: using a movement that is opposite to the movement that created it – using the eccentric contraction.
Now that the simple mechanics of tension accumulation and release have been explained, we can explain the mechanics from a physiological perspective. As discussed in the T-Shirt Analogy, muscle contractions can cause sarcomeres to bind together. However, it is important to clarify that sarcomeres do not bind during all three muscle contractions but rather during only one: the concentric contraction. The reason for this is because sarcomeres generate force in only one direction. This is the reason why the body needs balancing [antagonistic] muscles to perform opposite actions (e.g. the bicep bends the elbow and tricep straightens the elbow). It is the nature of this one-directional force that causes sarcomeres to bind during concentric contractions. This is illustrated by the hanging weight example which shows how the links can only bunch up and become “stuck” when they are being pulled together by moving from a lengthened to shortened state (i.e. concentric contraction).
Coincidently, it is the nature of this one-directional force that also enables sarcomeres to “un-bind” during eccentric contractions. Since the eccentric contraction is exactly opposite of the concentric contraction, [it provides the force needed during the balancing [antagonistic] movement to reverse the tension-building effects of concentric contractions.] This can be illustrated using the Chain Link Analogy where the tissue bound into a knot is no longer functional but the surrounding unbound tissue is and can still contract.
If the functional tissue (sarcomeres) surrounding a knot (area of tension) is shortened and then contracted (loaded) and forcibly lengthened (i.e. an eccentric contraction), then the outer functional sarcomeres adjacent to the non-functional sarcomeres within knot grip to each other and work to pull apart the knotted sarcomeres, thus releasing the tension. Isometric contractions are used in conjunction with eccentric contractions as a transitional phase from concentric to eccentric contractions by providing a constant load at the edges of knots. Isometrics also have an unbinding effect on knots, although it is much weaker than that of eccentrics.
As illustrated, force is required to remove muscle tension and is the reason why Yoga and other passive stretching activities are not effective tools when it is specifically muscle tension that needs to be removed. Instead, these activities are removing tension from another system of the body: the fascia.
The next Learning Lesson introduces fascia and explains why other modalities commonly thought to release muscle tension are actually only releasing fascial tension.